NEW YORK (CNN) -- New York is set to become the latest state to open the door for medical marijuana, with Gov. Andrew Cuomo to take executive action to let select hospitals dispense it to select patients, according to two advocates briefed on the plan.

State Assemblyman Richard Gottfried, who has been a leading proponent of more comprehensive legislation for medical marijuana in New York, said he learned about the executive action in a conversation Saturday afternoon with members of the governor's staff.

It paves the way for a "limited and cumbersome program," but nonetheless is a step forward on the issue, according to Gottfried.

"I'm thrilled that the governor has taken this action," the assemblyman said. "This is a very key interim step."

News of the governor's initiative was first reported by The New York Times.

Cuomo's office did not respond Saturday to CNN's requests for comment on the matter.

Medical marijuana is hardly unprecedented in the United States. Twenty states and the District of Columbia now allow it in some form -- among them Colorado, where as of January 1 it's legal to sell marijuana to those 21 or older -- according to info compiled by the National Conference of State Legislatures. (In addition, Maryland has a limited program for research.) The momentum has picked up of late, with most of these efforts taking effect over the past decade.

The states where there is medical marijuana include Connecticut, Vermont and New Jersey, each of which border New York. And yet the Empire State has not joined them. Versions of the Compassionate Care Act pushed by Gottfried have passed the state Assembly, only to stall in the Senate.

Cuomo is acting without the legislature's OK, though what he's doing is legal, according to Gottfried, whose district includes much of Midtown Manhattan. He explained that the governor is acting on powers granted through a law passed in 1980 in setting the stage for a highly regulated system that's less liberal than many other medical marijuana setups nationwide.

Here's how it would work, according to Gottfried: Under Cuomo's directive, the state health department would take charge by setting up the guidelines and picking hospitals that would take part. These hospitals would then have panels of people who decide, on a person-by-person basis, which patients qualify for medical marijuana.

It has yet to be determined where the medical marijuana -- or the elements of it that might be dispensed -- will come from, including who might produce it.

Gottfried estimated that tens of thousands of people could get medical marijuana by virtue of this policy change, though he insisted it is no substitute for a more complete, far-reaching program.

"(Cuomo) can take (this step) without the need for further legislation," the Manhattan legislator said. "But to have a truly comprehensive and well-working system will take legislation."

Gabriel Sayegh -- the New York state director for the Drug Policy Alliance, which describes itself as a "national advocacy leader of drug law reform" -- agrees, saying that it too will push for broader medical marijuana laws in the state.

He learned about this latest measure in a call Saturday from the governor's office, saying the proposal originated there and describing it the same basic way as Gottfried.

Even as he pushes for something bigger, Sayegh praised the governor for taking what he called an "exciting" initial step.

"It's tremendous," Sayegh said. "We applaud him coming out on this. It's going to help us build momentum to build a permanent program."

CNN's Kristina Sgueglia reported from New York, and CNN's Greg Botelho reported and wrote from Atlanta.